Barcelona were beaten 2-0 by Valencia at the Mestalla Stadium, while Atletico Madrid slipped down to fifth after a 0-0 draw at home to Leganes.
Here are the results from Week 21 in La Liga, and the updated standings:
Here's the team of the week.
GK: Alex Remiro, Real Sociedad
A glance at the 3-0 result suggests La Real had things all their own way as they beat Mallorca on Sunday.
Goalkeeper Remiro was vital for the hosts at the Anoeta Stadium, though, making two key saves to keep the game goalless in the first half before a second-half flurry earned them all three points.
DEF: Roberto Rosales, Leganes
Leganes started the weekend bottom of the table and would not have expected to get anything from their visit to the Wanda Metropolitano.
A fine defensive display saw them earn a point, though, and Rosales was heavily involved, winning four aerial duels, completing two tackles, and making four interceptions, three clearances and one block in the 90 minutes.
DEF: Nacho, Real Madrid
Making only his fifth La Liga appearance of the season, Nacho's excellent 78th-minute header ensured Real took full advantage of Barcelona's defeat against Los Che:
As well as making the key intervention at one end, the Spaniard was also crucial to Real keeping a clean sheet as he made four tackles. No other player on the pitch made more.
DEF: Sergio Reguilon, Sevilla
Like Nacho, Reguilon contributed at both ends for his side as Sevilla won 2-0 at the Ramon Sanchez-Pizjuan Stadium.
He made three tackles, an interception and two clearances in his defensive role, and he also set up Nolito for Sevilla's second goal after a fine run down the left flank.
DEF: Ferland Mendy, Real Madrid
Mendy matched Nacho's game-high four tackles in Real's victory over Valladolid, and he also completed five dribbles, registered an interception and made two clearances.
His most eye-catching contribution to Real's victory was blocking Sergi Guardiola's late shot from 12 yards to keep the score at 1-0.
MID: Geoffrey Kondogbia, Valencia
Any victory over Barcelona is satisfying, and Valencia were fully deserving of their 2-0 win on Saturday.
Kondogbia was the key man in the middle of the park for the hosts. The 26-year-old was a consistent thorn in Barcelona's side as he stopped attack after attack with his superb reading of the game:
MID: Portu, Real Sociedad
Portu was involved in just about everything good La Real did against Mallorca. He pulled the ball back to the edge of the six-yard box for Alexander Isak's 46th-minute opener and also laid off to Ander Barrenetxea for the second.
The Spaniard then got a goal of his own when he turned home from close range after Martin Odegaard's shot was blocked:
MID: Toni Kroos, Real Madrid
Kroos was typically superb in Real's Sunday victory, providing inch-perfect deliveries for both Casemiro's early disallowed goal and Nacho's winner.
He had more touches (105) than anyone else on the pitch, and he attempted more passes (90), with almost 98 per cent finding their mark.
FWD: Carlos Bacca, Villarreal
Bacca made the most of little service in Villarreal's 2-1 win over Alaves on Saturday.
He had only 19 touches in his 88 minutes on the pitch but won two aerial duels, made two clearances, completed one key pass and scored the opener with one of his two shots on goal.
FWD: Maxi Gomez, Valencia
Gomez must have thought he had missed out on a golden opportunity when his first-half penalty against Barcelona was saved by Marc-Andre ter Stegen.
But in the second half, his powerful shot was deflected into the back of the net by Jordi Alba, and he wrapped up the points 13 minutes from time with a lovely side-footed finish:
FWD: Luuk de Jong, Sevilla
Granada could barely keep a handle on De Jong for most of Saturday's clash in Seville.
The Dutchman headed home the opener in the 11th minute—one of his four shots on goal—and he was dominant in the air throughout, winning nine aerial duels, at least four more than anyone else on the pitch.
Stats from WhoScored.com